.Dd Aug 1, 2017
.Dt ADJTIMEX 1
.Sh NAME
.Nm adjtimex
.Nd access to kernel time controls and readouts
.Sh SYNOPSIS
.Nm
.Op Fl q
.Op Fl o Ar offset
.Op Fl f Ar freq
.Op Fl p Ar pll-time-constant
.Sh DESCRIPTION
.Nm
reads and optionally sets adjustment parameters for the Linux system
clock.  This program provides shell-level access to the system call
.Xr adjtimex 2 ,
which actually manipulates the
.Nm timex
structure.  All parameters are left alone unless asked to change with
the corresponding option.  By default, the values of the
.Nm timex
structure on return from
.Xr adjtimex 2
are printed, along with helpful hints about what
.Nm
switches control them.
.Pp
Mortal users may view all these parameters; only the superuser may
change them.
.Sh OPTIONS
.Bl -tag -width Ds
.It Fl q
quiet mode, do not print anything
.It Fl o Ar offset
Time offset in microseconds.
.It Fl -f Ar freq
Frequency adjust, in integer kernel units (65536 units is one
part-per-million).  Positive values make the system clock run fast.
.It Fl t Ar tick
Microseconds per tick, nominally 10000.  Coarse corrections (within 100
ppm) to clock frequency are better made here than with
.Fl f .
.It Fl p Ar pll-time-constant
Rate
.El
.Sh SEE ALSO
.Xr adjtimex 2 ,
.Xr tickadj 1 ,
.Xr /usr/include/linux/timex.h
.Pp
An independent implementation of similar functionality was
written by Steven Dick and Jim Van Zandt, see
.Lk http://www.ibiblio.org/pub/Linux/system/admin/time/adjtimex.lsm
.Sh BUGS
Every writable member of the
.Nm timex
structure should be settable from this program.
.Sh AUTHOR
Larry Doolittle <larry@doolittle.boa.org>
